Industrial robot

Abstract

The present invention is to provide an industrial robot, which is placed in vacuum for use, capable of efficiently cooling down hand- or arm-driving motors which are arranged inside the arm in air. The industrial robot is provided with a motor for rotating a second arm unit with respect to a first arm unit, a motor for rotating a hand with respect to the second arm unit, a reduction gear for reducing the rotation of the motor and transmitting it to the second arm unit, and a reduction gear for reducing the rotation of the motor and transmitting it to the hand; the hand and the arm are placed in vacuum. The reduction gears and are coaxially arranged so that the center of rotation of the second arm unit with respect to the first arm unit coincides with the axial centers of the reduction gears. The interior space of the hollow first arm unit is kept at atmospheric pressure in which the motors and the reduction gears are arranged.

What is claimed is: 
     
       1. An industrial robot for use with an object-to-be-handled, the industrial robot comprising:
 a main body unit; 
 an arm having a first arm unit, which is rotatably linked to said main body unit at a base end of the first arm unit, and a second arm unit which is rotatably linked to a front end of said first arm section at a base end of the second arm; 
 a hand which is rotatably linked to a front end of said second arm unit; 
 a first motor structured to rotate said second arm unit with respect to said first arm unit; 
 a second motor structured to rotate said hand with respect to said second arm unit; 
 a first reduction gear structured to reduce the rotation of said first motor and transmitting it to said second arm unit; and 
 a second reduction gear structured to reduce the rotation of said second motor and transmitting it to said hand; 
 wherein said hand and said arm are arranged in vacuum; 
 said first reduction gear and said second reduction gear are hollow reduction gears in which a through hole is formed in the centers thereof in the radial direction; 
 said first reduction gear and said second reduction gear are arranged coaxially on top of the other so that the center of rotation of said second arm unit with respect to said first arm unit is coaxial with axial centers of said first reduction gear and said second reduction gear, and said first reduction gear and said second reduction gear configure part of a first joint section connecting said first arm unit and said second arm unit; 
 said first motor, said second motor, said first reduction gear and said second reduction gear are arranged in an interior space of said first arm unit or said second arm unit which is formed hollow; and 
 said interior space is at atmospheric pressure. 
 
     
     
       2. The industrial robot as set forth in  claim 1  wherein, when said object-to-be-handled is taken out of a storage unit, in which objects-to-be-handled to be mounted on said hand are stored, or into said storage unit, said first arm unit and said hand rotate such that an angle of rotation of said first arm unit with respect to said main body unit is the same as an angle of rotation of said hand with respect to said second arm unit and a direction of rotation of said first arm unit with respect to said main body unit is opposite a direction of rotation of said hand with respect to said second arm unit. 
     
     
       3. The industrial robot as set forth in  claim 1  wherein said first arm unit is attached to said main body unit to extend from said main body unit to one side in the horizontal direction; and
 a counter weight which extends from said main body unit to the other side in the horizontal direction is attached to said first arm unit.